The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Along with the popularization of terminal devices such as fixed telephones and mobile phones, people's work and life have become more convenient as they may communicate with each other through the terminal devices at any time. However, terminal devices also bring troubles to their users. For example, as no user wants to be disturbed by unimportant phone calls at night or during leisure time, a user may turn off the terminal device, which, however, makes it possible for the user to miss important calls. If the user keeps the terminal on at night or during leisure time, there are indeed unimportant calls coming in during such periods, some of which are even harassing calls.
Terminal devices include fixed terminals and mobile terminals, and it is comparatively easy to turn off mobile terminals while the only way to turn off a fixed phone is to disconnect the telephone line, which is very inconvenient for the user. Moreover, turning off terminals, mobile or fixed, will bring other problems: the user will not get any phone calls when the terminal device is turned off, and others will not be able to contact the user even with very important business matters. And the user needs to turn on the terminal again when he needs to use the terminal. It is convenient to turn off or turn on mobile terminals, but it is common that a user forgets to turn on a fixed terminal. Thus the user will not get the phone calls from anyone through the terminal if it is not turned on again.
A user may also utilize the secretary service currently offered by a mobile communication system, but the service is applied to mobile terminals only. The user of a mobile terminal may customize the settings of his secretary station; for instance, the user who does not want to be disturbed by phone calls may request the secretary station to record voice messages for the calling users and send the messages to the called user. Therefore when the secretary receives a phone call for the user, it will ask the calling user to leave a message and then inform the called user by a short message or other means. The called user calls the secretary station to get the voice message left for him by the calling user. The called user may decide whether to call back according to the contents of the voice message, and thus will not be disturbed by incoming calls.
However, the secretary service is a paid service, i.e. the users of the service need to pay for it. The secretary station only converts incoming calls into short messages or other forms of notice to the called user, so the called user receives short messages or other messages instead of calls and is still somewhat disturbed. In this sense, the solution is not a perfect one. Besides, the short messages from the secretary station to the called user may be delayed or even lost, and the called user may not read the short messages in time. For example, as short messages are not real-time communication and users usually set gentle, weak or even mute short-message notifying sounds, it is common for a user to fail to handle a short message in time and accordingly fail to handle an urgent business in time.
Another solution is to set an incoming call filter. For instance, blacklists and whitelists can be used to protect users from the disturbance of unimportant phone calls while guaranteeing that important calls will never be missed. For example, the whitelist solution comprises: setting a whitelist of calling numbers that are allowed to access the called terminal; when the called terminal enables the whitelist function, only the calling numbers in the whitelist may access the called terminal. The whitelist solution may solve the above-mentioned problem to a large extent, but the authorized calling numbers are limited in the solution. When a user A needs to call a user C in emergency, although the cellular phone number of the user A is in the whitelist, the user A, as his cellular phone is out of power, may have to call with a user B's cellular phone, the number of which is not in the whitelist. In that case, the user A is unable to call through a number in the whitelist so that the user A will not be able to contact user C. The blacklist solution comprises: setting a blacklist of calling numbers that are not allowed to access the called terminal, when the called terminal enables the blacklist function, the incoming calls from the numbers in the blacklist will be refused. The blacklist solution is unable to block incoming calls from the number outside the blacklist. For example, harassing calls from public telephones are not blocked by the blacklist solution. What's more, the maintenance of the blacklist and the whitelist is complicated.